Field of the Invention
The present invention relates to an image processing device and an image processing method.
Description of the Related Art
When inclination, distortion or other problems are contained in an image formed on a sheet based on original image data by using an image forming apparatus, positional deviation of the image from the original position may be produced. This positional deviation is corrected by switching an address used for reading the original image data from a memory in accordance with the amount of positional deviation of the image. In this case, positions of respective pixels contained in the original image data are shifted to cancel the positional deviation produced in the formed image (for example, see JP 2008-148291 A).
A method currently proposed realizes reduction of the capacity of the memory necessary for storing the original image data by compressing the image data in units of a block, roughly shifting the positions of the respective pixels in units of this block, and then finely shifting the positions of the respective pixels after expanding the original image data (for example, see JP 2000-280525 A).
According to this method, the positions of the respective pixels are shifted only in units of one pixel. In this case, a considerable gap is produced in the image as a result of shifts of the respective pixels of the original image data when the original resolution of the original image data is low. This gap may deteriorate image quality.
For reducing visibility of this gap, there is proposed a further method which divides the unit of shift into a unit of one block, a unit of one pixel, and a unit smaller than one pixel to allow correction in stages (for example, see JP 2009-141544 A).
According to the method noted above, the shift in a unit smaller than one pixel is realized by interpolation. In this case, the shift based on interpolation becomes a rough shift when the original resolution of the original image data is low. The rough shift produces a considerable gap at the portion of interpolation, thereby deteriorating image quality.